Filter walls by base constraint

Hi, i’m at the beginning of using dynamo.
I want to select all walls of my model, by a value parameter ( base constraint-----> name " ST-0 - Fondazioni". I tried to do as explained in this post
https://forum.dynamobim.com/t/select-elements-by-parameter/6371

but don’t work for me because it seems select all wall of my model

Someone can help me please ?
Many thanks